This invention relates to a dispersive microlens.
This invention relates in particular to a color separation microlens which is a single micro-optical element made up of a color separation grating which disperses color by orders and which is integrated with a refractive lens.
The color separation microlens separates the spectrum into distinct color spots and focuses these spots to a common plane. The spots fall at the locations of the different diffraction orders. The color separation is done by the grating and the focusing is done by the lens.
The color separation microlens of the present invention is an improvement over a blazed dispersive microlens disclosed in co-pending U.S. application Ser. No. 07/904,316 filed Jun. 25, 1992, by George Gal, inventor, and entitled "Dispersive Microlens".
The blazed dispersive microlens disclosed in co-pending U.S. application Ser. No. 07/904,316 is a single micro-optical element made up of a blazed diffraction integrated onto the surface of a refractive lens.
The blazed dispersive microlens stretches the colors of the incoming light from blue to red in a single diffraction order and focuses the light down to a single diffraction spot.
The blazed dispersive microlens separates colors into a single diffraction order.
The color separation microlens of the present invention separates colors into distinct blur spots in different diffraction orders.
The blazed diffraction microlens performs a linear stretch of color from one end of the waveband to the other.
The color content of the blur spots of the color separation microlens contains contributions from all the wavelengths in the spectral band, with the weighting of the spectral content dependent on the diffraction order.